JPH06294812A - Semiconductor acceleration sensor - Google Patents

Semiconductor acceleration sensor

Info

Publication number
JPH06294812A
JPH06294812A JP10768893A JP10768893A JPH06294812A JP H06294812 A JPH06294812 A JP H06294812A JP 10768893 A JP10768893 A JP 10768893A JP 10768893 A JP10768893 A JP 10768893A JP H06294812 A JPH06294812 A JP H06294812A
Authority
JP
Japan
Prior art keywords
elements
axis
piezoresistive
bob
weight
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP10768893A
Other languages
Japanese (ja)
Inventor
Masato Imai
正人 今井
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Denso Corp
Original Assignee
NipponDenso Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NipponDenso Co Ltd filed Critical NipponDenso Co Ltd
Priority to JP10768893A priority Critical patent/JPH06294812A/en
Priority to US08/198,052 priority patent/US5507182A/en
Publication of JPH06294812A publication Critical patent/JPH06294812A/en
Pending legal-status Critical Current

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Abstract

PURPOSE:To make beam small in size by connecting piezoresistance elements at neighbouring positions to the bob side and the fixing frame side by turns. CONSTITUTION:On 4 beams 1 supporting a bob 2, 4 piezoresistance elements a, d, e, h are provided by turns on fixing frame 3 side and bob 2 side, and a Wheatstone bridge circuit is constituted. The vibration of the beam 1 causes in-phase resistance change between the piezoresistance elements positioning on a diagonal among 4 elements a to h in the case the bob 2 vibrates in Z axis direction, and out-of-phase resistance change between the neighbouring elements. However, in the case rotational vibration of the other axis is included in the bob 2, in-phase resistance change is caused between the neighbouring piezoresistance elements positioned symmetrically to the rotation axis. So, by combining the two, resistance change component of the other axis are cancelled each other. Thus, only one combination of piezoelements a to h is formed on each beam 1, wiring is simple and beam 1 can be small-sized.

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【産業上の利用分野】本発明は、加速度を半導体歪みゲ
ージ(ピエゾ抵抗素子)センサーで検出する装置に関す
る。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting acceleration with a semiconductor strain gauge (piezoresistive element) sensor.

【0002】[0002]

【従来の技術】従来、4本の両持梁(ビーム)に設けら
れたピエゾ抵抗素子によって加速度を検知する半導体加
速度センサーはビームの取付面に垂直な方向の錘の振動
だけではなく、ビームの取付面内に回転軸を有する運動
モードを有するため検出したい信号以外の信号が混じっ
てしまう。そのため、それらの信号をキャンセルするよ
うな工夫が、例えば Stephen Terry,IEEE Solid State
Sensor and Accelerometer Workshop(1988)pp.114-116
等に提案されている。この提案はピエゾ抵抗素子を4本
のビームにそれぞれ2本ずつ両端に配置して、8個の素
子で特定のホイートストーンブリッジを組んで不要な振
動モードの信号をキャンセルするものである。
2. Description of the Related Art Conventionally, a semiconductor acceleration sensor for detecting acceleration by a piezoresistive element provided on four double-supported beams (beams) is not limited to the vibration of a weight in a direction perpendicular to the mounting surface of the beam but also the beam. Since the mounting surface has a motion mode having a rotation axis, signals other than the signal to be detected are mixed. Therefore, it is necessary to devise a method to cancel those signals, for example, Stephen Terry, IEEE Solid State.
Sensor and Accelerometer Workshop (1988) pp.114-116
Have been proposed. In this proposal, two piezoresistive elements are arranged at each end of each of four beams, and a specific Wheatstone bridge is formed by eight elements to cancel an unnecessary vibration mode signal.

【0003】[0003]

【発明が解決しようとする課題】しかしながら、上記の
提案では各両持梁に2本ずつピエゾ抵抗素子を設け、か
つそれらの接続が単純ではないため配線が多くなり、ビ
ームを小さくすることには限度がある。このことは所定
の検出範囲に対して設定する錘の質量を大きくせざるを
得ないことを意味し、結果として検出加速度に制限を与
えてしまい、より高感度な小型のセンサーを構成するた
めに障害となっていた。
However, in the above proposal, two piezoresistive elements are provided on each of the both-supported beams, and the connection between them is not simple, so that the number of wirings is increased and the beam is reduced. There is a limit. This means that there is no choice but to increase the mass of the weight to be set for the predetermined detection range, and as a result, it limits the detection acceleration, and in order to configure a highly sensitive small sensor, It was an obstacle.

【0004】[0004]

【課題を解決するための手段】上記の課題を解決するた
め本発明の構成は、三次元空間直交軸X,Y,Z 軸のX−Y
平面上で、X軸対称かつY軸対称な配置の、二組の平行
な合計4本の両持梁を有し、該4本の前記両持梁で固定
枠の内側の空間に支えられるX軸対称かつY軸対称の錘
でもって、前記両持梁に設けられたピエゾ抵抗素子によ
ってZ軸方向の加速度を検知する半導体加速度センサー
において、前記ピエゾ抵抗素子が4本の前記両持梁にそ
れぞれ一個ずつ合計4個、かつ、隣合う位置関係にある
前記ピエゾ抵抗素子がそれぞれ前記両持梁の錘側端部と
固定枠側端部とに交互に配置され、前記ピエゾ抵抗素子
は隣合う配置の素子どうしが接続されてループとなった
ホイートストーンブリッジ回路に構成され、相対するブ
リッジ端子が出力端子、残りのブリッジ端子が電源端子
であることからなることを特徴とする。
In order to solve the above-mentioned problems, the structure of the present invention has a three-dimensional space orthogonal axis X, Y, Z axis X-Y.
On a plane, there are two sets of parallel double-supported beams, which are arranged in X-axis symmetry and Y-axis symmetry in total, and are supported in the space inside the fixed frame by the four double-supported beams. In a semiconductor acceleration sensor for detecting acceleration in the Z-axis direction by a piezoresistive element provided on the both-supported beams with an axisymmetric and a Y-axis-symmetric weight, the piezoresistive elements are respectively provided on the four supported beams. A total of four piezoresistive elements, which are adjacent to each other, are alternately arranged at the weight-side end and the fixed frame-side end of the both-supported beams, respectively, and the piezoresistive elements are adjacently arranged. It is configured in a Wheatstone bridge circuit in which elements are connected to form a loop, and the opposing bridge terminal is an output terminal and the remaining bridge terminals are power terminals.

【0005】[0005]

【作用】ビームの振動は、錘がZ軸方向に振動する場合
では、4つの素子のうち、対角線に位置するピエゾ抵抗
素子どうしに同位相の抵抗変化が発生して、隣どうしの
素子間では位相が反対の抵抗変化となるが、錘に他軸の
回転振動が含まれる場合は、その回転軸対称に位置する
隣あったピエゾ抵抗素子間では、お互いに同相の抵抗変
化を発生するので、その二つを組み合わせれば他軸の抵
抗変化成分を相殺できる。従って、この4つの素子でホ
イートストーンブリッジを組んで信号を取り出す場合、
隣合った位置のピエゾ抵抗素子を錘側部と固定枠側とに
交互に、即ち本発明の示す配置でピエゾ抵抗素子をルー
プ状に接続すると、他軸の望ましくない信号はキャンセ
ルされる。
In the vibration of the beam, when the weight vibrates in the Z-axis direction, among the four elements, a piezoresistive element located diagonally causes a resistance change in the same phase, and between adjacent elements. Although the resistance changes in opposite phases, if the weight contains rotational vibration of another axis, resistance changes in the same phase will occur between adjacent piezoresistive elements that are positioned symmetrically with respect to the rotational axis. By combining the two, the resistance change component of the other axis can be offset. Therefore, when forming a Wheatstone bridge with these four elements and extracting the signal,
If adjacent piezoresistive elements are alternately arranged on the weight side and the fixed frame side, that is, if the piezoresistive elements are connected in a loop in the arrangement shown in the present invention, an undesired signal on another axis is canceled.

【0006】[0006]

【発明の効果】本発明の構成では、各ビームに一つのピ
エゾ抵抗素子が形成されればよく、そのため配線も少な
くて簡単で済み、他軸感度を含むことなくビームを小型
化した加速度センサーが形成できる。
According to the structure of the present invention, one piezoresistive element may be formed for each beam, and therefore the wiring is small and simple, and an acceleration sensor in which the beam is miniaturized without including sensitivity to other axes is provided. Can be formed.

【0007】[0007]

【実施例】【Example】

(第一実施例)以下、本発明を具体的な実施例に基づい
て説明する。図1は本発明を適用した構造の半導体加速
度センサーの模式平面図で、固定枠3の内側の空間4
に、XY平面に配置される錘2を支えている4本のビー
ム1上に、ピエゾ抵抗素子a〜hが4つ、交互に固定枠
側、錘側に位置している。このピエゾ抵抗素子は図2に
示すホイートストーンブリッジ回路を構成し、ブリッジ
の抵抗R1 〜R4 はそれぞれ図1(a) のa,d,e,h
に示す4つのピエゾ抵抗素子である。この固定枠3及び
錘2は半導体のウエハ状態からエッチングにより、くり
抜かれて形成される。ビーム1の部分は図1(b) に示す
K-K 部分の断面図の様に、ウエハの裏側からやはりエッ
チングで、薄肉部を設けることで形成する。
(First Embodiment) The present invention will be described below based on specific embodiments. FIG. 1 is a schematic plan view of a semiconductor acceleration sensor having a structure to which the present invention is applied, showing a space 4 inside a fixed frame 3.
Further, four piezoresistive elements a to h are alternately located on the fixed frame side and the weight side on the four beams 1 supporting the weight 2 arranged on the XY plane. This piezoresistive element constitutes the Wheatstone bridge circuit shown in FIG. 2, and the resistors R1 to R4 of the bridge are respectively a, d, e and h of FIG. 1 (a).
The four piezoresistive elements shown in FIG. The fixed frame 3 and the weight 2 are formed by being hollowed out from a semiconductor wafer state by etching. The part of beam 1 is shown in Fig. 1 (b).
As shown in the cross-sectional view of the KK part, it is also formed by etching from the back side of the wafer to provide a thin portion.

【0008】ビーム1の位置は錘が振動するモードを考
慮してなるべく検出軸以外の成分が入ってこないような
位置に決められる。これは検出目標や形状や錘の寸法等
の設計により変化する。しかしどのような寸法になって
も図1(a) に示すZ軸方向の動き以外にも錘の中心を通
るX軸またはY軸を軸とする回転運動が存在し、この振
動モードによる信号、即ち他軸感度が含まれてしまう。
The position of the beam 1 is determined in consideration of the mode in which the weight vibrates so that components other than the detection axis do not enter. This changes depending on the design of the detection target, the shape, the size of the weight, and the like. However, no matter what the size, in addition to the movement in the Z-axis direction shown in Fig. 1 (a), there is a rotational movement about the X-axis or Y-axis passing through the center of the weight. That is, the other axis sensitivity is included.

【0009】一例としてY軸を中心にして回転する振動
モードの場合に、bの部分がさがってdの部分が上がる
ような動きの場合は、aのピエゾ抵抗素子は伸張力を受
け、eのピエゾ抵抗素子は圧縮力を受けるので、aは抵
抗値が下がり、eは抵抗値が上がるが、この時、dのピ
エゾ抵抗素子とhのピエゾ抵抗素子との間でも同様な関
係の変動が発生するためブリッジのバランスは保たれる
ことになる。また、aとdとの間では両者とも伸張力を
受ける配置なので同じ抵抗変化が発生する関係になって
いる。錘が反対の方向に動く場合も同様で、同じ回転軸
側の隣合ったピエゾ抵抗素子はお互いに反対の抵抗変化
を生じ、回転対称に位置する隣のピエゾ抵抗素子どうし
は同相の抵抗変化を発生する。従って、ホイートストー
ンブリッジにおいては丁度出力端子に対してバランスを
保ったままの関係になり、このY軸の動きによる信号成
分は出力端子に出てこない。
As an example, in the case of a vibration mode of rotating around the Y-axis, in the case of a movement in which part b is raised and part d is raised, the piezoresistive element of a receives an extension force and Since the piezoresistive element receives a compressive force, the resistance value of a decreases and the resistance value of e increases. At this time, however, a similar variation occurs between the piezoresistive element of d and the piezoresistive element of h. Therefore, the balance of the bridge will be maintained. Further, since both a and d are arranged to receive an extension force, the same resistance change occurs. The same applies when the weights move in opposite directions.Adjacent piezoresistive elements on the same rotation axis side cause resistance changes that are opposite to each other, and adjacent piezoresistive elements that are rotationally symmetrical have the same phase resistance change. Occur. Therefore, in the Wheatstone bridge, there is a relationship in which the output terminal is kept balanced, and the signal component due to the movement of the Y axis does not appear at the output terminal.

【0010】この関係はX軸を軸として錘が回転運動す
る場合も同様であり、結果として錘の動きで信号に寄与
するのはZ軸方向の運動のみとなる。Z軸方向の振動の
際には、錘2が上に上がる時、ピエゾ抵抗a、hは圧縮
を受け、d、eは伸張の力を受けるので、ブリッジの各
抵抗はバランスを大きく崩す様に抵抗変化する。従っ
て、錘2のZ軸方向の並進運動以外に可能な運動はX、
Y軸を軸とする回転運動のみなので、結局上記の理由に
より、目標とするZ軸方向の加速度のみがほぼ正しく検
出できる。
This relationship is the same when the weight makes a rotational movement about the X axis, and as a result, only the movement in the Z axis direction contributes to the signal due to the movement of the weight. At the time of vibration in the Z-axis direction, when the weight 2 rises, the piezoresistors a and h receive compression, and d and e receive extension forces, so that the respective resistances of the bridge are significantly out of balance. Resistance changes. Therefore, the motions other than the translational motion of the weight 2 in the Z-axis direction are X,
Since only the rotational movement about the Y-axis is used, only the target acceleration in the Z-axis direction can be detected almost correctly for the above reason.

【0011】(第二実施例)ピエゾ抵抗素子の配置を図
1に示した他に、ビームの反対の端に置き換えたもの
(b,c,f,g の位置、図3の断面図参照)でも、構造に対
称性があるため同様な効果がある。
(Second Embodiment) In addition to the arrangement of the piezoresistive element shown in FIG. 1, it is replaced with the opposite end of the beam (positions of b, c, f and g, see the sectional view of FIG. 3). However, since the structure has symmetry, the same effect can be obtained.

【0012】従来は図5に示すホイートストーンブリッ
ジ回路で示すような8個のピエゾ抵抗素子を用いて図1
(a) のa〜h全ての位置にピエゾ抵抗素子を設け、同じ
ペアの素子内で他軸感度を相殺するようホイートストー
ンブリッジを組んでいたので、複雑な配線を必要とし、
ビーム部分に数本の配線を通さなくてはならなかった。
そのためビームの幅を小さくすることには限度があっ
た。今回の構成では各ビームに一つのピエゾ抵抗素子が
あるだけでよく、配線も最大2本通す事が出来ればよい
だけなのでかなり細くでき、センサー構造を小型化する
ことが出来る。
Conventionally, eight piezoresistive elements as shown in the Wheatstone bridge circuit shown in FIG. 5 are used in FIG.
Since piezoresistive elements were provided at all positions a to h in (a), and Wheatstone bridges were formed to cancel the sensitivity of other axes within the same pair of elements, complicated wiring was required,
I had to run several wires through the beam.
Therefore, there is a limit to reducing the beam width. With this configuration, only one piezoresistive element is required for each beam, and it is only necessary to be able to pass a maximum of two wires, so it can be made quite thin and the sensor structure can be downsized.

【0013】この構造をFEM(有限要素法)でシミュ
レーションすると、図4(a) 及び(b) の指向性欄(出力
に相当)で示されるように、8本のピエゾ抵抗素子を用
いた(b) に比べ、4本のピエゾ抵抗素子で構成した本発
明の場合でも、Z軸方向のみが大きく値を持ち、他の軸
の出力はほとんどなく、他軸感度の程度にはほとんど差
がない。即ちこれは4本の構成でも十分に他軸感度をキ
ャンセルできて、さらになお小型の加速度センサーが実
現できることを意味する。
When this structure is simulated by FEM (Finite Element Method), eight piezoresistive elements are used as shown in the directivity column (corresponding to output) in FIGS. 4 (a) and 4 (b) ( Compared to b), even in the case of the present invention composed of four piezoresistive elements, only the Z-axis direction has a large value, there is almost no output of the other axes, and there is almost no difference in the degree of sensitivity of the other axes. . That is, this means that the sensitivity of the other axis can be sufficiently canceled even with the configuration of four lines, and an even smaller acceleration sensor can be realized.

【0014】[0014]

【図面の簡単な説明】[Brief description of drawings]

【図1】本発明のピエゾ抵抗素子の配置を施した半導体
加速度センサーの模式図。
FIG. 1 is a schematic diagram of a semiconductor acceleration sensor in which a piezoresistive element of the present invention is arranged.

【図2】図1のピエゾ抵抗素子によるホイートストーン
ブリッジ回路図。
FIG. 2 is a Wheatstone bridge circuit diagram using the piezoresistive element of FIG.

【図3】本発明の第二実施例をしめすビーム部の断面
図。
FIG. 3 is a sectional view of a beam portion showing a second embodiment of the present invention.

【図4】FEM解析結果一覧図。FIG. 4 is a list of FEM analysis results.

【図5】従来のホイートストーンブリッジ回路図。FIG. 5 is a conventional Wheatstone bridge circuit diagram.

【符号の説明】[Explanation of symbols]

1 ビーム(梁) 2 錘 3 固定枠 a,d,e,h 本発明のピエゾ抵抗素子(歪みゲー
ジ) b,c,f,g 第二実施例、及び従来のピエゾ抵抗素
子の配置部分
DESCRIPTION OF SYMBOLS 1 beam (beam) 3 weight 3 fixed frame a, d, e, h Piezoresistive element (strain gauge) b, c, f, g of this invention 2nd Example and the arrangement | positioning part of the conventional piezoresistive element

Claims (1)

【特許請求の範囲】[Claims] 【請求項1】三次元空間直交軸X,Y,Z 軸のX−Y平面上
で、X軸対称かつY軸対称な配置の、二組の平行な合計
4本の両持梁を有し、該4本の前記両持梁で固定枠の内
側の空間に支えられるX軸対称かつY軸対称の錘でもっ
て、前記両持梁に設けられたピエゾ抵抗素子によってZ
軸方向の加速度を検知する半導体加速度センサーにおい
て、 前記ピエゾ抵抗素子が4本の前記両持梁にそれぞれ一個
ずつ合計4個、かつ、隣合う位置関係にある前記ピエゾ
抵抗素子がそれぞれ前記両持梁の錘側端部と固定枠側端
部とに交互に配置され、 前記ピエゾ抵抗素子は隣合う配置の素子どうしが接続さ
れてループとなったホイートストーンブリッジ回路に構
成され、相対するブリッジ端子が出力端子、残りのブリ
ッジ端子が電源端子であることからなることを特徴とす
る半導体加速度センサー。
1. Two sets of parallel double-supported beams are arranged in parallel with each other in an X-axis symmetric and a Y-axis symmetric arrangement on an XY plane of three-dimensional spatial orthogonal axes X, Y, Z axes. , A weight having X-axis symmetry and Y-axis symmetry supported by the four double-supported beams in a space inside a fixed frame, and Z by a piezoresistive element provided on the double-supported beams.
In a semiconductor acceleration sensor for detecting acceleration in the axial direction, a total of four piezoresistive elements, one for each of the two doubly supported beams, and the piezoresistive elements having an adjacent positional relationship, respectively. Are alternately arranged on the weight side end and the fixed frame side end, and the piezoresistive element is configured in a Wheatstone bridge circuit in which elements arranged adjacent to each other are connected to form a loop, and opposite bridge terminals Is an output terminal, and the remaining bridge terminals are power terminals, which is a semiconductor acceleration sensor.
JP10768893A 1993-02-18 1993-04-09 Semiconductor acceleration sensor Pending JPH06294812A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP10768893A JPH06294812A (en) 1993-04-09 1993-04-09 Semiconductor acceleration sensor
US08/198,052 US5507182A (en) 1993-02-18 1994-02-18 Semiconductor accelerometer with damperless structure

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP10768893A JPH06294812A (en) 1993-04-09 1993-04-09 Semiconductor acceleration sensor

Publications (1)

Publication Number Publication Date
JPH06294812A true JPH06294812A (en) 1994-10-21

Family

ID=14465451

Family Applications (1)

Application Number Title Priority Date Filing Date
JP10768893A Pending JPH06294812A (en) 1993-02-18 1993-04-09 Semiconductor acceleration sensor

Country Status (1)

Country Link
JP (1) JPH06294812A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10290792A (en) * 1997-04-18 1998-11-04 Toshiba Corp Biological magnetic field measuring instrument
US6683358B1 (en) 1997-11-11 2004-01-27 Asahi Kasei Kabushiki Kaisha Silicon integrated accelerometer
JP2007003211A (en) * 2005-06-21 2007-01-11 Sharp Corp Acceleration sensor and its output correction method
JP2014010021A (en) * 2012-06-29 2014-01-20 Kyowa Electron Instr Co Ltd Accelerometer

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10290792A (en) * 1997-04-18 1998-11-04 Toshiba Corp Biological magnetic field measuring instrument
US6683358B1 (en) 1997-11-11 2004-01-27 Asahi Kasei Kabushiki Kaisha Silicon integrated accelerometer
WO2004090556A1 (en) * 1997-11-11 2004-10-21 Makoto Ishida Silicon integrated acceleration sensor
JP2007003211A (en) * 2005-06-21 2007-01-11 Sharp Corp Acceleration sensor and its output correction method
JP2014010021A (en) * 2012-06-29 2014-01-20 Kyowa Electron Instr Co Ltd Accelerometer

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